Electric compensator.



G. A. BURNHAM.

ELECTRIC COMPENSATOR.

APPLICATION FILED SEPT. 15, 1909.

1,10,247 Patented May 18, 1915.

2 SHEETS-SHEET I.

G. A. BURNHAM.

ELECTRIC COM-PENSATOR.

APPLICATION FILED SEPT. 15, 1909.

Patented May 18, 1915.

2 SHEETS-SHEET wiinefisas,"

UNITED STATES. PATENT OFFICE.

GEORGE A. BURNHAII, 0F CLIFTONDALE, MASSACHUSETTS, ASSIGNOR TO SEARS B.

CONDIT, JB., OF BOSTON, MASSACHUSETTS.

ELEGTRIC COMPEHSATOR To all whom it may concern Be it known that I, GEORGE A. BURl IHAM, a citizen of the United States, residlng at Cliftondale, in the county of Essex and State of Massachusetts, have invented an Improvement in Electric Compensators, of

which the following description, in connec-v tion with the accompanying drawings, is a specification, like letters on the drawings representing like parts.

My invention has for its object the automatic compensation in a supply system whereby the voltage may be regulated at the, bus-bars to compensate for drop of potential under the varying conditions of service of a consumption circuit at another-point.

In carrying-out. my invention I provide .mechanism whose operation depends upon the variation in speed of motor-operated circuit making and breaking apparatus to vary the field excitation of the supply generator and regulate the voltage over wide ranges of load in the consumption circuit with a minimum amount of mechanism and light moving parts.

The constructional details of my invention and its advantages will be pointed out tern of distribution.

more at length in .the following description with referencetothe accompanying drawlngs. I v

Figure 1 is a diagrammatic new of my invention as applied to an alternating sysview as applied to a direct current system. Fig. 3 is a diagrammatic detail. Fig. 4 is a dlagrammatic view of a further develop ment or more complete embodiment of theinvention, applied to two or more machines operating in parallel. Fig. 5 is a central vertical transverse sectional view, partly broken away, of the rotary contact device. Fig 6 is a fragmentary transverse vertical section through the slotted portion of the shaft 49 of Fig. 5. i

Referring to Fig. 1, the feed wires 1, 2 are shown in connection with translating devices 3, the current being derived from an alternating generator whose armature is indicated at 4 and field magnet coil at 5, the latter being connected by wires 6, 7 to an exciter armature 8 and field coil 9. Connected across the wires 1, 2 is. a potential transformer 10, and in one of the tires, as

2, is a "current transformer 11 leadin \bV wires 12, 13, 14, 15 to a contact-ma Specification of Letters Patent.

Fig. 2 is a similar-= Patented May 18, 1915. Application filed September 15, 1909. Serial No. 517,821.

voltmeter coil 16 whose core 17 controls the I 'cuit, core 17 being responsive to both current and voltage. It will be understood that any suitable contact-making voltmeter may be employed which is adapted for the work:

that shown comprises two differentially act ing coils, one 16 tending to hold contacts 21, 20 open against spring 22 at normal load, the companion coil exerting an opposing force tending to close the contacts on predetermined increase of load. An adjustable resistance 23 connects by a wire 24 with the lever 18 at one end and by a wire 25 with the contact 21 at the other end, and thence by a wire 26 to a motor 27. The energy for said motor may be derived from any suitable source, the circuit being shown in Fig.1 as completed by a wire 28 from a transformer 29 whose primary is connected across the feeder wires 1, 2, the secondary the volt meter. speed of the motor 27 will vary with the "voltage of the circuit 1, 2 and may be set as required for a normal speed by adjustable resistance 23. The motor is provided with a bevel pinion 31 meshing with a gear 32 which operates the rotary contact portion of my compensating mechanism, the device in general being indicated at 33, and shown in detail in Fig. 5. Wires 34, 35 lead from the contact device 33 respectively to the 0pposite ends of the adjustable rheostat 36 of the exciter, preferably being capable of being varied by hand. Instead of connecting the wire 34 from the end of the rheostat directly to the field coil 9 of the exciter, I interpose in series with the coil 9 an automatic cutout device shown as comprising a solenoid 37, one end of whose winding 38 leads to the field coil, and the other 39 leads to the rheostat and wire 34. The core 40 of said solenoid 37 is normally held up by an 3 adjustable spring 41 and carries at its optact-plate closing the circuit at proper times between contacts 45, 46, the former connected by wire 47 with one end of the rheostat, and the latter by a wire 48 withan intermediate tap of the rheostat. Thus when current passes through the rheostat 36 of avalue such that its drop of potential across the wires 34, 35 would injure the contact device 33, this is prevented by short-circuiting a portion of the rheostat through the closing of the short-circuit 47, 48 at the contacts 45, 46. In Fig. 5 I have shown the rotary contact device in enlarged detail, where it will be seen that the gear 32 is fast on the lower end of a shaft 49 mounted at its lower end in a guide bearing 50, and at its upper end in a thrust ball-bearing 51 carried by a central standard 52 of a surrounding cylindrical shell 53. On the upper end of this shaft 49 is mounted an arm 54 held against rotation thereon by any suitable means, but free to move longitudinally against the resistance of a spring 56, adjusted by nuts 57. At its free end the arm 54 carries an electric contact 58 freely movable radially in a brush-holder 59, maintained normally under outward tendency by a spring 60 and connected by a flexible conductor 61 to any suitable rotary conducting portion, preferably to the arm 54. The holder 59 has an upwardly extending portion 62 preferably vertically adjustable by a slot and bolt connection 63 with relation to the arm 54. Connected with the rotary shaft 49 is a stop, herein shown as an anti-friction wheel 64 mounted in a slot 65 in the shaft 49 on which bears the curved shoe end 66 of a lever 67 pivoted at 68 on a boss 69 of the arm 54, said lever 67 having a depending portion 70 carrying an adjustable weight 71. Above the shell 53 is a complementary cylindrical shell 72 separated from the former by insulation 73 which extends diagonally of theaXis of said two shells, which latter carry binding posts 74, 75. A pressed-glass cover 76 is mounted on the top of the upper shell and is removably retained by spring clips 7 7.

In Fig. 4 I have indicated a further feature of my invention when the same is used in connection with a plurality of generators, two being shown as sufficient to make said application understood. The leads 34, 35 from the compensator member 33, the same as already described, are connected respectively to regulator bus-bars 78, 9, across which are switches 80, 81, one for each machine. Inasmuch as the latter are the same and the Wiring the same as already described, I have shown merely the rheostat of each machine, herein indicated at 82, 83, respectively, and corresponding to the rheostat 36 above, from which rheostat leadwires 84, 85 and 86, 87 to the field and armature respectively of the generator. Thus the operator by throwing the switch 80 in, effects the same single arrangement shown in Figs. 1 and 2, and by throwing in also the switch 81 he causes the two generators to be regulated simultaneously by the same compensating mechanism. fhus, it will be readily seen that my compensating mechanism is capable of use with a plurality of generators, and does not require a separate compensating apparatus for each generator. Preferably a condenser 88 is interposed across the leads from the compensator 33 to take care of any undue sparking that would otherwise occur.

In operation the motor 27 continuously rotates the shaft 49, and hence moves the contact 58 in continuous engagement with the shells of the member 53, its relative period of engagement with one and the other of said shells depending upon the vertical position of the contact 58. Said vertical position is governed by the speed of rotation of the shaft 49, whichthrows the weight 71 outwardly by centrifugal force to a greater or less extent according to said speed, andthereby through the action of the camlike shoe end of the weight raises the arm 54 and with it the contact 58, or permits the same to fall more or less. It wil be observed that this centrifugal actior dependent upon the speed of rotation he shaft 49. and hence upon the speed c: motor 27, and the latter varies according to the variations in voltage of the circuit whose variations are to be compensated. Whenever the load 3 is increased the compound coil 16 holds the contacts 20, 21 closed, thereby cutting out the resistance 23 and permitting the motor 27 to increase its speed. This increase of speed of the motor correspondingly increases the speed of rotation of the shaft 49, which throws out the centrifugal Weight 71, and thereby raises the contact 58 so that as it rotates it maintains contact with the shell 72 longer than before, with the result that the rheostat 36 of the exciter circuit is short-circuited for a greater aggregate length of time than previously, which increases the exciter voltage, thereby raising the voltage of the generator 4, 5, which raises the voltage of the line 1, 2 to the extent necessary to counteract the drop due to increase of load. Thereupon the contacts 20, 21 open, with the result that the motor slows down, the centrifugal weight falls, restoring the rotary contact 58 to a lower position where the aggregate closure of the short-circuit around rheostat 36 is of shorter duration. Thus as the load 3 varies the speed of the motor and the position of brush vary simultaneously. The brush and all its connected parts are exceedingly light, so that their momentum does not appreciably influence the speed of the motor. The rotation of the brush prevents it from heating by exposure to air, and as it moves on the inside of the shell a hard, effective contact is maintained. The motor might be 9? used without resistance 23, but not so efiectually. The resistance permits the speed to be set more definitely for a normal load, and moreover reduces the intensity of sparking at the contacts 20, 21.

I, will now explain the action of the automatic cutout cooperating with the rheostat .36. On heavy load the potential drop across .at a variable rate of vibration accordingly as the effect of the current coil is large or small relatively to the tension of the spring 22; when the cutout operates it reduces the field resistance and lowers the potential 7 across the contacts of the intermittent interrupter 33 thereby protecting the contacts from danger of b rning.

In Fig. 2 I have shown the invention as applied to a direct current system. The line wires 1, 2 are connected directly to the direct current generator 8, 9, the coils in the voltmeter being operated from wires 89, 90, and a shunt 91 and wires 92, 93 across the line as shown, a wire 94 connecting from the line Wire 2 to the lever 18, and a Wire 95 from controlling rheostat 36 becomes so high as tov the line wire 1 to the motor to complete the circuit of the latter.

In Fig. 3 I have indicated a battery 96 for operating the motor instead of the potential transformer 29 of Fig. 1, it being understood that the motor may be supplied with energy from any suitable source.

In all cases the operation of the automatic compensating mechanism is substantially operations to establish automatic compensation for voltage drop and current in the circuit of the generator or systems being regulated, and Whenever the current in the endanger the contacts the relay 37 operates to short-circuit. a part of the rheostat. The

spring 41 of said relay is so adjusted that when a predetermined current value passes through the field coil 9 andsaid relay, the contact disk 42 is drawn down to short-circuit a part of the resistance. The dashpot 44 prevents momentary changes in the field circuit from causing an operation of the relay. The compensation is caused by a combination of the vertical position of the contact 58 and the rotary speed of said contact. Both of these are positive and definite, and are mutually dependent, so that the vertical position is due to centrifugal action under varying speed, and efi'ects eflective ters-Patent is the same, goingthrough the same cycle of,

regulation in the way described. The circuit which includes wires 34:, 35, which is an auxiliary circuit with relation to the main circuit, is continuously interrupted by the compensator and thereby acts on the maincircuit through the generator by automatically governing the duration of interruptions in the auxiliary circuit to a predetermined extent as determined by the motor whose speed changes in response to the vari-' ations in the main circuit.

Having thus described my invention, what I claim as new and desire tp secure by Let- 1. An apparatus of the kind described including a main circuit, a field circuit, a field resistance, and automatic make and break means for varying the value of the field strength, containing means for varying the length of interruption,'said last mentioned varying means being controlled. by a speed changing device for simultaneously changing the speed of interruption and also governing said controlled varying means to change the length of interruption.

2. An apparatus of the kind described including a'main circuit, a field circuit, a field resistance, .automatic make and break means for varying the value of the field strength responsive to a variable speed actuator and containing means under the control of said variable speed actuator to vary the length of interruption, said variable speed actuator simultaneously changing the speed of interruption of said makeand break means and also governing said controlled varylng means to vary the length of interruptlon.

3. An apparatus of the-kind described, in-

cluding a maincircuit, a field circuit and automatic means for varying the value of the field strength including make and break mechanism, anda variable speed device responsive to variations in voltage in the main circuit for changing the proportion of the make and break.

4:. In an apparatus of the kind described,

including a main circuit, a field circuit,

automatic makeand break means for varying the value of the field current, and a variable speed operating device for operating said make and break means variable in response' to variations in voltage in said main circuit, the relative duration of make and break being dependent upon the speed changes of said operating device.

5. An apparatus of the kind described in cluding a main circuit, a generator, a field circuit for said generator, means for Varying the value of the field strength in accordance With speed changes including a make and break device whose relative duration of make and break is dependent upon speed changes in said device, and operating means for the latter having a variable speed in response to variations of voltage in the main circuit.

6. In an apparatus of the kind described, a main circuit, a generator, a field circuit for said generator, an automatic means for varying the value of the field strength having two relatively movable make and break members, and centrifugal means whose speed is responsive to variations in voltage in said main circuit for automatically varying the relative duration of the make and break. v

7. In an apparatus of the kind described, a main circuit, a generator, a field circuit for the generator, and automatic means for varying the value of the field current having two relatively movable make and break members, one of which is stationary and the other rotary relatively thereto and whose position for varying the relative duration of the make and break is due to changes in its speed, and means for automatically varying the speed of rotation of said rotary member in response to variation in voltage in said main circuit.

8. An apparatus of the kind described, in cluding a field circuit, a resistance, and automatic means for varying the value of the field strength by said resistance, including a stationary cylindrical conductor member composed .of a plurality of parts insulated from each other, a cotiperating rotary contact whose position for governing the relative duration of the make and break is due to changes in the speed of rotation thereof, and means for driving said contact.

9. An apparatus of the kind described, including a field circuit, a resistance, and automatic means for varying the value of the field strength by said resistance, including a stationary cylindrical conductor composed of a plurality of parts insulated from each other, a cooperating rotary contact Whose position with relation to the stationary member is dependent solely upon changes in the speed of rotation thereof, and means for driving said contact at a variable speed.

,10. An apparatus of the kind described, including a generator, a field circuit,a resistance, and automatic means for varying the value of the field strength by said resistance, including a stationary cylindrical conducting member composed 'of a plurality of parts insulated from each other, and a cotiperating rotary contact having two movements responsive to conditions of the generator, one movement-being longitudinally of said cylindrical member and th other concentrically thereof.

11. An apparatus of the kind described, including a field circuit, a resistance, and automatic means for varying the value of the field strength by said resistance, including a stationary cylindrical conductor member composed of a plurality of parts insulated from each other, a cotiperating rotary contact having provision for movement longitudinally of said cylindrical member and also concentrically thereof, and centrifugal means for governing the position of said contact in accordance with the speed of movement thereof.

12. In an apparatus of the kind described, a main circuit, a continuously interrupted auxiliary circuit which reacts on said main circuit to regulate the voltage thereof, means for continuously interrupting said auxiliary circuit including two relatively movable make and break members, one of which rotates with relation to the other, and means responsive to variations in said maiircircuit for automatically varying the speed of said rotation to the extent required to maintain the desired voltage in the main circuit.

13. In an apparatus of the kind described, a main circuit, a continuously interrupted auxiliary circuit which reacts on said main circuit, means for continuously interrupting said auxiliary circuit including two relatively movable make and break members, one of which rotates with relation to the other, means responsive to variations in the main circuit for automatically varying the speed of said rotation, and centrifugal means for varying the duration of the interruptions in said auxiliary circuit in addition to the variations of said duration caused by said variations in the speed of rotation.

14. In an apparatus of the kind described, a line circuit, a compensator apparatus for compensating changes of voltage in said line circuit, including two relatively movable make and break members, at least one of which is continuously moving, actuating means responsive'to variations in voltage in the line circuit for moving at a variable speed said continuously moving member, and separate means governed by said actuating means for changing to a predetermined extent the duration of the periods of interruption in addition to such changes therein as are due to the change in the speed of said movement.

15. A main circuit, a generator, a field circuit therefor, a rheostat in the field circuit, short-circuiting means for the rheostat, an automaticmake and break regulator for the field circuit, and automatic means responsive to changes of the field current for operating said short-circuiting means Whenever the field current reaches a predetermined value.

16. main circuit, a generator therefor, a field circuit, a rheostatcontrolling the field circuit, an automatic make and break regulator for varying field current, a relay responsive to predetermined electrical conditions of the field circuit, a normally open short-circuit around a portion of the rheostat, and contact means controlled by said relay for closing said short-circuit whenever the field current reaches a value suffi- I ing means therefor including two make and break members, one of which is continuously movmg and whose variations in relative position of make andbreak are due solely to changes in its speed of movement, operating means for moving the latter in response to changes in voltage in said main circuit, an operating circuit for said operating means including a make and break regulating device, and a resistance around the contacts of said make and break device.

18. The combination in a voltage regulator for dynamo-electric machines, of a generator, a field circuit thereof, rapid field circuit interrupting means normally liable to sparking, an auxiliary circuit controlling the field circuit, and spark reducing means in said auxiliary circuit comprising a hand' adjusted rheostat for the field circuit, and an automatic cutout operative only upon the occurrence of predetermined current in the field circuit adapted to lower the potential at the interrupting means.

19. The combination in a voltage regulator for dynamo-electric machines, of a generator, a field circuit thereofirapid field circuit interrupting means, an auxiliary circuit controlling the field circuit, means in said auxiliary circuit for preventing destructive sparking at the interrupting means, and an automatic cutout responsive to predetermined electrical conditions of the field circuit for controlling the spark reducing means.

20. In combination, a main circuit, a generator, its field and regulating resistance, a rapidly operating make and break device for intermittingly shunting said resistance, and an automatic switching means responsive to the field current for varying the.

value of the resistance and thereby reducing potential across the make and break evice. 4

21. The combination with a main circuit, a generator and its field circuit, of a voltage regulator containing means producing'rapid make and break pulsations in said field circuit and normally liable tosparking, a re sistance in said field circuit, and automatic cutout means responsive to field current to cut out a. portion of said resistance upon the occurrence of predetermined electrical conditions, said cutout having a tendency to respond in unison with the operation of the regulator, and retarding means for preventing the operation of the cutout, said retardmg means being ineffective to prevent the operation of the cutout within predetermined current limits.

22. The combination with a main circuit, agenerator and its field circuit including a rheostat, of a voltage regulator responsive to variations of voltage in said main circuit for varying the value of the field current including make and break contacts for shunting the field rheostat, and automatic safety means responsive to the field current for preventing destructive arcing between said make -and break contacts.

23. In an apparatus of the kind described, a main circuit, a generator, a rheostat in series with the field circuit of the generator, an automatic make and break means for varying the field strength in responseto variations in the electrical conditions of said circuit, and an automatic cutout responsive to field current forcutting out a portion of the resistance.

24. In an apparatus of the kind described, a main circuit, a generator, a resistance in series with the field circuit of said generator, an automatic make and break compensating means for varying the field strength in'respouse to variations in said circuit, and an automatic cutout for cutting out a portion of said resistance whenever the current in the field circuit reaches a predetermined "value. v

25. In an apparatus of the kind described, a main circuit, a generator, a field circuit, a rheostat in series in the field circuit, an automatic make and break means for varying thefield strength in accordance with the variations in the main circuit, a normally open shunt circuit around a portion of said rheostat, a relay controlling said shunt, and contact means operated by said relay for closing said shunt upon the flow of a predetermined current in said field circuit to prevent injury to said make and break means.

26. In an apparatus of the kind described, a main circuit, a continuously interrupted auxiliary circuit, means whereby the auxiliary circuit reacts on the main circuit, means for continuously interrupting said auxiliary circuit, including two relatively movablev make and break members one of which rotates with relation to the other, a rotary actuator, and means responsive to variations in said main circuit for automatically varying said rotation to the extent required to maintain the desired voltage in the main circuit. 27. In an apparatus of the kind described, the combination of a main circuit, a generator and its field circuit, a voltage regulator containing intermittent interrupting means of varying duration shunting a resistance in series with the field circuit, differentially acting current and voltage coils governi g the interrupting means, and mechanism including an automatic cutout responsive to predetermined electrical conditions in said field circuit, for reducing sparking at the interrupting means.

' 28. In an apparatus of the kind described, a line circuit, automatic compensating means therefor including two make and break members, one of which is continuously moving, a driving motor for moving the latter, an energizing circuit for said motor an automatic regulating device in said energizing circuit responsive to variations in said line circuit, and a shunt resistance around said regulating device for giving smooth changes of speed regulation to said motor by said regulating device.

29. A compensator device for variations in voltage in a line circuit, including a stationary vertical cylinder, a central rotary shaft within said cylinder, a contact carried by said shaft to engage the cylinder, said cylinder being composed of a plurality of parts having adjacent wedge-shaped portions which terminate obliquely to the axis of the shaft alternately engaged by said contact as the shaft rotates, at least one of said parts being a conductor, means for rotating said shaft, and means for varying the position of said contact lengthwise of the cylinder in response to variations of voltage in said line circuit.

30. A compensator device for variations in voltage in a line circuit, including a stationary vertical cylinder, a central rotary shaft within said cylinder, a contact carried by said shaft to engage said cylinder, said cylinder being composed of a plurality of parts having adjacent wedge-shaped portions which terminate obliquely to the axis of the shaft alternately engaged by said contact as the shaft rotates, at least one of said parts being a conductor, and means for rotating said shaft responsive to variations in voltage in the line circuit.

31. A compensator device for variations in voltage in a line circuit, including a stationary vertical cylinder, a central rotary shaft within said cylinder, a contact carried by said shaft to engage said cylinder, said cylinder being composed of a plurality of parts having adjacent wedge-shaped portions which terminate obliquely to the axis of the shaft alternately engaged by said contact as the shaft rotates, at least one of said parts being a conductor, a motor for driving said shaft at a variable speed responsive to variations in voltage in said line circuit, and means for shifting said contact transversely to the direction of its rotation in accordance with the variations in the speed of said rotationu 32A compensator device for variations in voltage in 'a line circuit, including a stationary vertical cylinder, a central rotary shaft within said cylinder, a contact carried by said shaft to engage said cylinder movable with said shaft and also longitudinally thereof, said cylinder being composed of a plurality of parts having adjacent wedgeshaped portions which terminate obliquely to the axis of the shaft alternately engaged by said contact as the shaft rotates, at least one of said partsbeing a conductor, means for rotating said shaft, and centrifugal. means for moving said contact longitudinally of said shaft in accordance with the speed of the shaft.

33. A compensator device for variations in voltage in a line circuit, including a stationary vertical cylinder, a central rotary shaft within said cylinder, a contact carried by said shaft to engage said cylinder movable with said shaft and also longitudinally thereof, said cylinder being composed of a plurality of parts having adjacent wedgeshaped portions which terminate obliquely to the axis of the shaft, alternately engaged by said contact as the shaft rotates, at least one of said parts being a conductor, means for rotating said shaft, centrifugal means for moving said contact longitudinally of said shaftin accordance with the speed of the shaft, and adjusting means for varying the entrifugal effect.

The combination with a dynamo-electric machine, and a resistor in the field circuit thereof, of means for adjusting the effective value of the resistor, and means for separately adjusting the value of said resistor in accordance with variations of an electrical condition of the dynamo-electric machine.

35. The combination with a main circuit, a dynamo-electric machine associated therewith, and an exciter for the dynamo-electric machine, of a resistor in the eXciter field circuit, means'for establishing and interrupting a shunt circuit to said resistor in accordance with variations in the electrical condiname to this specification, in the presence oftwo subscribing Witnesses.

GEORGE A. BURNHAM.

Witnesses:

A. L. HORTON, C. O. BADEAU. 

